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In the process of metal parts fabricated by Laser Melting Deposition (LMD), a high temperature gradient will generate due to the instantaneous high laser energy input, which will cause residual stress in the formed part of metal parts, the residual stress will result in defects like warping deformation or even cracking. In this paper, a finite element method based on inherent strain method is proposed to predict the deformation of metal parts fabricated by LMD. Firstly, combing with the birth and death element technology, a local model is established to simulate the layer-by-layer deposition in the LMD forming process, and the values of inherent strain is obtained. Secondly, the obtained inherent strain values is applied to large-sized part layer by layer, and the final deformation of large-sized part is calculated. Based on the proposed method, the efficiency of deformation prediction of large-sized metal parts fabricated by LMD could be effectively improved.

Based on the Paris model of fatigue crack growth theory, the fatigue crack growth behaviour of Center Crack Tension (CCT) specimens of laser melting deposited 12CrNi2 alloy steel is studied by extended finite element method (XFEM). The crack growth rules and fatigue life are analyzed by experiment and finite element simulation. The experimental results are in good agreement with the finite element results, which verifies the accuracy of XFEM method to simulate the fatigue crack growth behaviour of laser melting deposited 12CrNi2 alloy steel components. Based on this, the effects of initial crack direction and load amplitude on fatigue crack growth behaviour are discussed. The results indicate that even if the initial crack direction is different, the crack will finally propagate in a direction perpendicular to the load. With the increase of the load amplitude, the fatigue life of the specimen with initial crack decreases exponentially.

Autoclaved aerated concrete waste (AACW) was used as a raw material to prepare nucleation seed for acceleration of Portland cement. Nano AACW seed with median particle size of 324 nm was prepared by wet grinding method. Both the electrical conductivity and pH value of nano AACW suspension were obviously improved. Both the setting times and intensity of the main hydration heat peak were promoted by nano AACW, indicating the possibility of AACW suspension as nucleation seed. The early age compressive strength before 3 days was also clearly improved by nano AACW, with no negative effect on the late age strength. Furthermore, the reduced CH content with dosage of nano AACW indicates that nano AACW not only plays a role of nucleation seed in cement hydration, but also has a certain pozzolanic reaction.

A four-winding inductive filtering transformer (FW-IFT) that is of a special filtering winding is designed according to the equivalent zero impedance principle of multi-winding transformer. The inductive filtering method with the series connection of the passive filter and the filtering winding of a FW-IFT is proposed to deal with the problem of reactive power and harmonics in a high-voltage distribution network. The equivalent circuit model of the FW-IFT is analyzed in detail from the inductive filtering condition. Then, the voltage equations are established, and harmonic suppression factor is introduced to analyze its filtering characteristics. The simulation and experimental results are provided to verify the feasibility of implementing the inductive filtering for the FW-IFT.

Steel slag is a solid waste generated from the steelmaking process. With a very low utilization rate of 30% in China, a high discharging cost of steel slag is inevitable so that it is imperative to dispose of steel slag by new technology. In this study, steel slag was refined by wet-grinding technology to apply on cement. The results showed that the initial setting time and final setting time were prolonged by the increased dosage of 3 μm steel slag. Although the viscosity of wet-grinding steel slag – cement specimens increased significantly, the shear-thinning phenomenon happened by mechanical mixing. The wet-grinding specimens presented a higher hydration heat than that of raw steel slag specimens, and the microstructure of 3 μm-40% (3 μm steel slag mixed with cement as a dosage of 40%) is much denser and show more hydration products than that of raw-40% (raw steel slag mixed with cement as a dosage of 40%) which results in an enhanced compressive strength that could be guaranteed by the dosage of 20% (3 d), 30% (28 d) and 40% (60 d) under the condition of 3 μm steel slag incorporation with lower autogenous shrinkage. Hemicarboaluminate peak was found in wet-grinding specimens that show a higher calcium sulphoaluminate to calcium. The wet-grinding steel slag CO2 emission and cost showed a downward trend compared with cement.

This work reports the synthesis of multi-layer graphene-coated, La and Sc co-doped Li4Ti5O12 (LLTSO/G) anodes for Li-ion battery where the co-doped LTO was synthesized via a modified sol-gel method. High-resolution transmission electron microscope (HRTEM) analysis revealed that graphene layers occupied the space between these three-dimensional LLTSO particles which provides a convenient transport path for electrons and thus resulted in a great rate electrode capability. The revisable capacity of this LLTSO is 176 mAh g−1 at 0.5C, after coating LLTSO with graphene the electrode exhibited excellent electrochemical performance, the discharge capacity is 101 mAh g−1 at 40C, much higher than the uncoated one (85 mAh g−1 at 40C). LLTSO/G was proved to be a promising high rate electrode material for lithium batteries.

Recently, several randomized controlled trials (RCT) investigating the effectiveness of decompressive craniectomy in the context of neurocritical illnesses have been completed. Thus, a meta-analysis to update the current evidence regarding the effects of decompressive craniectomy is necessary. We searched PUBMED, EMBASE and the Cochrane Central Register of Controlled Trials. Other sources, including internet-based clinical trial registries and grey literature, were also searched. After searching the literature, two investigators independently performed literature screening, assessing the quality of the included trials and extracting the data. The outcome measures included the composite outcome of death or dependence and the risk of death. Ten RCT were included: seven RCT were on malignant middle cerebral artery infarction (MCAI) and three were on severe traumatic brain injury (TBI). Decompressive craniectomy significantly reduced the risk of death for patients suffering malignant MCAI (risk ratio [RR] 0.46, 95% confidence interval [CI]: 0.36-0.59, P

In order to improve the power quality of 220kV transformer substations in power system, the harmonic currents on the 110kV and 35kV sides can flow into the superconducting loop which is composed of the inductive filter winding of four-winding inductive filter transformer and the inductive filter device, and thus the currents on 220kV side are pollute-less. The parameters of inductive filter device in the loop is the key to affect the entire filtering performance. Therefore, an immune genetic algorithm(IGA) of improved operator is applied to optimize the design of inductive filter device in this paper, which uses the total investment cost of the device, the reactive power compensation and the filtering performance as the optimized objectives. Besides the ability of global searching of the genetic algorithm(GA), the IGA involves the mechanisms of immune system such as memory cell and antibody diversity-keeping. By updating the memory cell bank and dynamically adjusting the immune function through the improved operator, the convergent speed of the IGA is accelerated and the global optimal solution is obtained. Simulation results show that the IGA is more effective than the traditional algorithm(TA) for optimizing the design of the inductive filter device.

Li 4 Ti 5 O 12 was successfully synthesized by a modified solid-state reaction method with an in situ coating process. The powders were characterized by X-ray diffraction, BET surface area and scanning electron microscopy. Sub-micron Li 4 Ti 5 O 12 oxides, with a high phase purity and accurate stoichiometry, were obtained after calcination at 800 °C for 7 h. The pure Li 4 Ti 5 O 12 electrode material showed a much higher surface area and specific capacity than the one without the ultra-high speed nano-pulverization pretreatment process. Excellent reversible high-rate capability was achieved as 137 mAh g −1 at 10C, 107 mAh g −1 at 20C, 76 mAh g −1 at 40C. The result of the cycling performance showed high capacity retention of about 100% for all charge/discharge rates after 10 cycles. Electrochemical impedance spectra tests demonstrated that the lithium-ion diffusivity in Li 4 Ti 5 O 12 was improved significantly after the pretreatment, which indicated that the ultra-high speed nano-pulverization treated Li 4 Ti 5 O 12 with high dispersion and smooth particle surface would be a promising high-rate anode material for lithium-ion battery.

A novel and highly efficient photocatalyst, Eosin Y-sensitized Pt-intercalated nanotube Pt/HLa Nb2O7, was found to be very active for hydrogen generation within triethanolamine (TEOA) solution as the electron donor under visible-light irradiation (λ420 nm). The photocatalysts were characterized by X-ray diffraction (XRD), UV-vis diffuse reflectance spectra (DRS), scan electron microscope (SEM) and energy dispersive spectrometer (EDS). The results showed that the significant enhancement of photocatalytic activity was achieved via Pt intercalating and subsequent dye sensitization of Pt/HLaNb2O7. The highest rate for hydrogen evolution was 4.45 mmol·g-1·h-1under irradiation with a wavelength longer than 420 nm, and the probable mechanism of photosensitized hydrogen evolution have also been discussed.

A novel photoelectrochemical solar cell was prepared by combining a Sb 2 S 3 -sensitized photoactive electrode, polyaniline nanobelts and a Pt counter electrode to form sandwich structure. The incident photo-to-current conversion efficiency measurement found that the cell without any sensitizers just showed a very narrow photo-response wavelength region from 300 nm to 400 nm, while the Sb 2 S 3 -sensitized cell showed a broad photo-response wavelength region from 275 nm to 600 nm and much higher efficiency in converting ultraviolet light to electricity than in converting visible light. By optimizing chemical bath deposition duration of 2.5 h, the cell showed high photovoltaic performance with 6.92 mA cm −2 short-circuit current density, 1.098 V open-circuit voltage, 0.497 fill factor, and 3.78% power conversion efficiency, being greatly enhanced compared with that of the cell without any sensitizers (1.09 mA cm −2 , 0.866 V, 0.477, 0.45%).

A simple printed ultrawideband (UWB) antenna with reconfigurable band-rejected characteristics is proposed. The antenna was fabricated on an FR-4 epoxy substrate and has a volume of 40.0 × 32.0 × 1.0 mm3. The simulated and measured results show that the antenna has nearly omnidirectional patterns, stable gain, and an available impedance bandwidth of 9.38 GHz which covers 2.34–11.72 GHz. By etching two slots in the radiator, band- notched features centered at 3.5 and 5.5GHz are achieved. With adding two microelectromechanical system switches across slots, the band-rejected characteristics can be reconfigurable and the proposed antenna is capable of operating among none or single or dual band-notched modes. Meanwhile, to discuss the mechanisms of the band-rejected properties, the conceptual equivalent circuit models are presented. © 2012 Wiley Periodicals, Inc. Microwave Opt Technol Lett 54:2401–2405, 2012; View this article online at wileyonlinelibrary.com. DOI 10.1002/mop.27061

In this paper, a novel slot-ring coupling antenna with reconfigurable circular polarization is presented. The antenna consists of Wilkinson power divider and a slot-ring with perturbations. By controlling the states of the switches, the antenna can achieve right-hand circular polarization (RHCP), left-hand circular polarization (LHCP) in the same direction, respectively. The proposed antenna is designed and simulated using Ansoft HFSS. The measured results of the fabricated antenna are in good agreement with the simulated. Both measured and simulated results of the antenna are presented and discussed.

We employ the parallel computing technology to study numerically the three-dimensional structure of quantized vortices of Bose–Einstein condensates. For anisotropic cases, the bending process of vortices is described in detail by the decrease of Gross–Pitaevskii energy. A completely straight vortex and the steady and symmetrical multiple-vortex configurations are obtained. We analyse the effect of initial conditions and angular velocity on the number and shape of vortices.

Objective To assess the effect of intensive insulin therapy (IIT) for preventing postoperative infection in patients with traumatic brain injury (TBI). Methods In total, 88 patients with TBI were randomly divided into 2 groups, 44 in each group. One group (group ITT) received IIT and the other group (group CIT) received conventional insulin therapy (CIT). This study was conducted between February 2013 and January 2016. Outcomes included infection rate, mortality, and neurological outcome (measured by the Glasgow Outcome Scale [GOS]). Results A total of 81 patients completed the study. IIT showed greater efficacy than CIT, with a decreased infection rate in the IIT group compared to the CIT group (31.9% vs 52.3%, P = 0.03), and also a reduced duration of stay in intensive care unit (ICU) (IIT group, 4.5 ± 2.1 days vs CIT group, 5.7 ± 2.8 days, P = 0.02). In addition, a significant difference in scores on the GOS scale was observed between the 2 groups (P = 0.04). The mortality rates in hospital and at the 26-week follow-up were similar between the 2 groups. Conclusion IIT leads to a reduced infection rate, shorter stays in ICU, and improved neurological outcome.

Background A wealth of evidence based on the randomized controlled trials (RCTs) has indicated that surgery may be a better choice in the management of primary intracerebral hemorrhage (ICH) compared to conservative treatment. However, there is considerable controversy over selecting appropriate surgical procedures for ICH. Thus, this meta-analysis was performed to assess the effects of stereotactic aspiration compared to craniotomy in patients with ICH. Methods According to the study strategy, we searched PUBMED, EMBASE and Cochrane Central Register of Controlled Trials. Other sources such as the internet-based clinical trial registries, relevant journals and the lists of references were also searched. After literature searching, two investigators independently performed literature screening, assessment of quality of the included trials and data extraction. The outcome measures included death or dependence, total risk of complication, and the risk of rebleeding, gastrointestinal hemorrhage and systematic infection. Results Four RCTs with 2996 participants were included. The quality of the included trials was acceptable. Stereotactic aspiration significantly decreased the odds of death or dependence at the final follow-up (odds ratio (OR): 0.80, 95% confidence interval (CI): 0.69–0.93; P = 0.004) and the risk of intracerebral rebleeding (OR: 0.44, 95% CI: 0.26–0.74; P = 0.002) compared to craniotomy with no significant heterogeneity among the study results. Conclusions The present meta-analysis provides evidence that the stereotactic aspiration may be associated with a reduction in the odds of being dead or dependent in primary ICH, which should be interpreted with caution. Further trials are needed to identify those patients most likely to benefit from the stereotactic aspiration.

Background A wealth of evidence from animal experiments has indicated that hypertonic saline (HS) maybe a better choice for fluid resuscitation in traumatic hypovolemic shock in comparison with conventional isotonic saline. However, the results of several clinical trials raised controversies on the superiority of fluid resuscitation with HS. This meta-analysis was performed to better understand the efficacy of HS in patients with traumatic hypovolemic shock comparing with isotonic saline. Materials and methods According to the search strategy, we searched the PubMed, EMBASE, and the Cochrane Central Register of Controlled Trials, which was completed on October 2013. After literature searching, two investigators independently performed the literature screening, assessment of quality of the included trials, and data extraction. Disagreements were resolved by consensus or by a third investigator if needed. The outcomes included mortality, blood pressure, fluid requirement, and serum sodium. Results Six randomized controlled trials were included in the meta-analysis. The pooled risk ratio for mortality at discharge was 0.96 (95% confidence interval [CI], 0.82–1.14), whereas the pooled mean difference for the change in systolic blood pressure from baseline and the level of serum sodium after infusion was 6.47 (95% CI, 1.31–11.63) and 7.94 (95% CI, 7.38–8.51), respectively. Current data were insufficient to evaluate the effect of HS on the fluid requirement for the resuscitation. Conclusions The present meta-analysis was unable to demonstrate a clinically important improvement in mortality after the HS administration. Moreover, we observed HS administration maybe accompanied with significant increase in blood pressure and serum sodium.

Porous silicon was prepared by anodization of a p/p + epitaxial c-Si wafer. Its structure was examined by electron microscopy, Raman spectroscopy, and infrared spectroscopy. The results of the examination show that there is a thin molecular film containing Si-H, Si-0 and Si-H 2 crystalline slices, and that there is a thin molecular film containing Si-H, Si-0 and Si-H 2 bonds at the surface of the slices. Some solar cells were fabricated from the porous Si wafers, and about 7% efficiency was obtained.

Biogas is a kind of rich resource and cheap renewable biomass energy and wildly used in rural and remote mountain area in China. Based on methane gas combustion characteristic, the model of miniature gasoline generator refitted was selected. A kind of miniature gasoline generator was refitted by increasing the compression ratio, regulating the ignition advance angle, selecting and designing precipitator, desulfurization device, gas pressure stabilizer and mixer unit etc., to form a complete set of miniature biogas generator systems. This paper analyzed the biogas composition and the combustion characteristics of biogas, and described the methods of increasing the compression ratio and regulating the ignition advance angle, and the analysis and computation processes of designing gas pressure stabilizer and mixer. The miniature biogas generator designed and refitted can start normally and operate stably, and all the performance indexes accord with dynamo requirements, generating power can satisfy a household daily electricity demand.

Recent studies have shown that graphene paper (GP) is a promising candidate for novel applications in energy storage systems such as electrical batteries and supercapacitors. In this study, a low-cost and free-standing GP was produced by graphene oxide paper (GOP) in the thermal reduction method which heated GOP slowly to 500 °C in a special fixture. In the process of reduction, oxygen functional groups were decomposed and graphene oxide (GO) sheets were reduced to grapene sheets. Moreover, the smooth paper-like structure was maintained by the protection of the special fixture during the heat treatment. The GP paper showed good electrochemical property. The electrical conductivity of the GP reached 182 S cm −1 after the decomposition of oxygen functional groups. The GP as binder-free anodes of lithium ion batteries afforded a capacity of 576 mAh g −1 with good cycling stability.

Ignition performance of liquid fuel spray at various fuel/air ratios and the effect of gaseous fuel addition on ignition improvement were investigated on a gas turbine combustor test facility. Distribution of fuel/air ratio with gaseous fuel addition through the spark plug and the fuel nozzle into the flame tube was measured respectively. The universal ignition criterion derived from developed thermal explosion physical model at maximum chemical reaction rate for heterogeneous mixture ignition and the empirical formula of evaporation coefficient in fuel spray are in good agreement with experimental data obtained in dense and dilute fuel spray, and homogeneous mixture.Copyright © 1981 by ASME